Our invention relates generally to semiconductor devices, and more specifically to a semiconductor device such as a rectifier diode having a p-n junction of an improved voltage withstanding capability. Our invention also specifically concerns a method of making such a p-n junction semiconductor device.
A variety of expedients have been suggested and used for higher breakdown voltages of p-n junction devices. Typical of such known expedients are the field plate and the floating field limiting ring. The field plate is disclosed in the article entitled "Relation between Oxide Thickness and the Breakdown Voltage of a Planar Junction with Field Relief Electrode" by O'neil et al. in the Vol. ED-26, No. 7, issue of IEEE Transactions of Electron Devices. The field ring is disclosed in the article entitled "Theory and Breakdown Voltage for Planar Devices with a Single Field Limiting Ring" by Adler et al. in the Vol. ED-24, No. 2 issue of IEEE Transactions on Electron Devices.
Still another known construction includes a floating Schottky barrier metal electrode on the semiconductor substrate, in substitution for the field ring, as taught by Japanese Unexamined Patent Publication No. 54-118781.